An implementation of the Gear rolling hash function.
The Gear hashing function is a fast, rolling hash function that is well suited
for content-defined chunking. It is used as a building block for the FastCDC
algorithm which is implemented by the chunk iterator (
with the Gear hasher.
This implementation is based on the FastCDC  and Ddelta  papers.
 Wen Xia, Yukon Zhou, Dan Feng, Yu Hua, Yuchong Hu, Yucheng Zhang, and Qing Liu. “FastCDC: A Fast and Efficient Content-Defined Chunking Approach for Data Deduplication” USENIX ATC’16, June 2016, 101–14. DOI 10.5555/3026959.3026969.
 Xia, Wen, Hong Jiang, Dan Feng, Lei Tian, Min Fu, and Yukun Zhou. “Ddelta: A Deduplication-Inspired Fast Delta Compression Approach” Performance Evaluation 79 (September 2014): 258–72. DOI 10.1016/j.peva.2014.07.016.